Haliclona : Nervous System

Abstract

Early sponges diverged from the metazoan lineage and have a genetic repertoire representative of our common ancestor. Sponges do not possess a neural system, neither specialized cells to conduct cell depolarization, but have neural toolkits that were probably coopted for it. Sensitive epithelial cells and myoepithelial cells conducting waves of generalized cell depolarization and contraction constitute the neural toolkit present in sponges. Their genomes have pre‐ and postsynaptic genes. Secondary loss of neural system is another possibility, and the genes for synapsis might serve another secretory propose in sponge, but secondary loss is not commonly accepted.